{“reqId”:“43tl6XL5YN534yqrMWeG”,“level”:3,“time”:“2018-03-06T12:39:58+00:00”,“remoteAddr”:"",“user”:"–",“app”:“PHP”,“method”:"–",“url”:"–",“message”:“Class ‘PDO’ not found at /usr/share/nextcloud/lib/private/Setup.php#129”,"userAg

I tested with the Nethserver-testing package which is needed as it includes php 71. Without the testing package you get the Nextcloud update wizard after an update, with the testing package Nextcloud is upgraded.